Synthesis of Vinyl Glycosides and Carbohydrate Vinyl Ethers from Mixed Acetals: A Hetero‐Diels—Alder Approach to Deoxygenated Disaccharides.

Abstract

Deoxygenated Disaccharides. -A new method for the synthesis of the title vinyl ethers is presented. Readily prepared carbohydrate-derived mixed acetals (III) and (X) undergo elimination reactions under conditions developed by Gassman to give the target compounds. With a view to the synthesis of antibiotics, hetero-Diels-Alder reactions of (IV) with unsaturated carbonyl compound (VI) are performed to give the corresponding cycloadducts (VII)/(VIII) which may be used as precursors for deoxygenated disaccharides. Since acetylated vinyl glycoside (V) is not available by the Gassman method because of side reactions, an alternative synthesis is presented, involving the reductive debenzylation of ether (IVa) followed by acetylation. -(HUGHES, K. D.; NGUYEN, T.-L. N.; DYCKMAN, D.; DULAY, D.; BOYKO, W. J.; GIULIANO*, R. M.; Tetrahedron: Asymmetry 16 (2005) 1, 273-282; Dep. Chem., Villanova Univ., Villanova, PA 19085, USA; Eng.) -Klein 23-205